@article {3565,
	title = {Ablation of the inferior olive prevents H-reflex down-conditioning in rats.},
	journal = {Journal of neurophysiology},
	volume = {115},
	year = {2016},
	month = {Mar},
	pages = {1630{\textendash}1636},
	abstract = {We evaluated the role of the inferior olive (IO) in acquisition of the spinal cord plasticity that underlies H-reflex down-conditioning, a simple motor skill. The IO was chemically ablated before a 50-day exposure to an operant conditioning protocol that rewarded a smaller soleus H-reflex. In normal rats, down-conditioning succeeds (i.e., H-reflex size decreases at least 20\%) in 80\% of animals. Down-conditioning failed in every IO-ablated rat (P< 0.001 vs. normal rats). IO ablation itself had no long-term effect on H-reflex size. These results indicate that the IO is essential for acquisition of a down-conditioned H-reflex. With previous data, they support the hypothesis that IO and cortical inputs to cerebellum enable the cerebellum to guide sensorimotor cortex plasticity that produces and maintains the spinal cord plasticity that underlies the down-conditioned H-reflex. They help to further define H-reflex conditioning as a model for understanding motor learning and as a new approach to enhancing functional recovery after trauma or disease.},
	keywords = {Spinal Cord},
	issn = {1522-1598},
	doi = {10.1152/jn.01069.2015},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/26792888},
	author = {Xiang Yang Chen and Wang, Yu and Yi Chen and Chen, Lu and Jonathan Wolpaw}
}
@article {3566,
	title = {The inferior olive is essential for long-term maintenance of a simple motor skill.},
	journal = {Journal of neurophysiology},
	volume = {116},
	year = {2016},
	month = {Oct},
	pages = {1946{\textendash}1955},
	abstract = {The inferior olive (IO) is essential for operant down-conditioning of the rat soleus H-reflex, a simple motor skill. To evaluate the role of the IO in long-term maintenance of this skill, the H-reflex was down-conditioned over 50 days, the IO was chemically ablated, and down-conditioning continued for up to 102 more days. H-reflex size just before IO ablation averaged 62({\textpm}2 SE)\% of its initial value (P < 0.001 vs. initial). After IO ablation, H-reflex size rose to 75-80\% over ?10 days, remained there for ?30 days, rose over 10 days to above its initial value, and averaged 140({\textpm}14)\% for the final 10 days of study (P < 0.01 vs. initial). This two-stage loss of down-conditioning maintenance correlated with IO neuronal loss (r = 0.75, P < 0.01) and was similar to the loss of down-conditioning that follows ablation of the cerebellar output nuclei dentate and interpositus. In control (i.e., unconditioned) rats, IO ablation has no long-term effect on H-reflex size. These results indicate that the IO is essential for long-term maintenance of a down-conditioned H-reflex. With previous data, they support the hypothesis that IO and cortical inputs to cerebellum combine to produce cerebellar plasticity that produces sensorimotor cortex plasticity that produces spinal cord plasticity that produces the smaller H-reflex. H-reflex down-conditioning appears to depend on a hierarchy of plasticity that may be guided by the IO and begin in the cerebellum. Similar hierarchies may underlie other motor learning.},
	issn = {1522-1598},
	doi = {10.1152/jn.00085.2016},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/27535367},
	author = {Xiang Yang Chen and Wang, Yu and Yi Chen and Chen, Lu and Jonathan Wolpaw}
}
@article {3390,
	title = {Locomotor impact of beneficial or nonbeneficial H-reflex conditioning after spinal cord injury.},
	journal = {J Neurophysiol},
	volume = {111},
	year = {2014},
	month = {03/2014},
	pages = {1249-58},
	abstract = {When new motor learning changes neurons and synapses in the spinal cord, it may affect previously learned behaviors that depend on the same spinal neurons and synapses. To explore these effects, we used operant conditioning to strengthen or weaken the right soleus H-reflex pathway in rats in which a right spinal cord contusion had impaired locomotion. When up-conditioning increased the H-reflex, locomotion improved. Steps became longer, and step-cycle asymmetry (i.e., limping) disappeared. In contrast, when down-conditioning decreased the H-reflex, locomotion did not worsen. Steps did not become shorter, and asymmetry did not increase. Electromyographic and kinematic analyses explained how H-reflex increase improved locomotion and why H-reflex decrease did not further impair it. Although the impact of up-conditioning or down-conditioning on the H-reflex pathway was still present during locomotion, only up-conditioning affected the soleus locomotor burst. Additionally, compensatory plasticity apparently prevented the weaker H-reflex pathway caused by down-conditioning from weakening the locomotor burst and further impairing locomotion. The results support the hypothesis that the state of the spinal cord is a "negotiated equilibrium" that serves all the behaviors that depend on it. When new learning changes the spinal cord, old behaviors undergo concurrent relearning that preserves or improves their key features. Thus, if an old behavior has been impaired by trauma or disease, spinal reflex conditioning, by changing a specific pathway and triggering a new negotiation, may enable recovery beyond that achieved simply by practicing the old behavior. Spinal reflex conditioning protocols might complement other neurorehabilitation methods and enhance recovery.},
	keywords = {Animals, Conditioning, Operant, Female, H-Reflex, Learning, Locomotion, Male, Rats, Rats, Sprague-Dawley, Spinal Cord Injuries},
	issn = {1522-1598},
	doi = {10.1152/jn.00756.2013},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/24371288},
	author = {Yi Chen and Lu Chen and Liu, Rongliang and Wang, Yu and Xiang Yang Chen and Jonathan Wolpaw}
}
@article {3383,
	title = {Persistent beneficial impact of H-reflex conditioning in spinal cord-injured rats.},
	journal = {J Neurophysiol},
	volume = {112},
	year = {2014},
	month = {11/2014},
	pages = {2374-81},
	abstract = {<p>Operant conditioning of a spinal cord reflex can improve locomotion in rats and humans with incomplete spinal cord injury. This study examined the persistence of its beneficial effects. In rats in which a right lateral column contusion injury had produced asymmetric locomotion, up-conditioning of the right soleus H-reflex eliminated the asymmetry while down-conditioning had no effect. After the 50-day conditioning period ended, the H-reflex was monitored for 100 [{\textpm}9 (SD)] (range 79-108) more days and locomotion was then reevaluated. After conditioning ended in up-conditioned rats, the H-reflex continued to increase, and locomotion continued to improve. In down-conditioned rats, the H-reflex decrease gradually disappeared after conditioning ended, and locomotion at the end of data collection remained as impaired as it had been before and immediately after down-conditioning. The persistence (and further progression) of H-reflex increase but not H-reflex decrease in these spinal cord-injured rats is consistent with the fact that up-conditioning improved their locomotion while down-conditioning did not. That is, even after up-conditioning ended, the up-conditioned H-reflex pathway remained adaptive because it improved locomotion. The persistence and further enhancement of the locomotor improvement indicates that spinal reflex conditioning protocols might supplement current therapies and enhance neurorehabilitation. They may be especially useful when significant spinal cord regeneration becomes possible and precise methods for retraining the regenerated spinal cord are needed.</p>},
	keywords = {H-reflex conditioning, Learning, Locomotion, Memory, Motor control, Rehabilitation, spinal cord injury, spinal cord plasticity},
	issn = {1522-1598},
	doi = {10.1152/jn.00422.2014},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/25143542},
	author = {Yi Chen and Lu Chen and Wang, Yu and Jonathan Wolpaw and Xiang Yang Chen}
}
@article {3084,
	title = {Cortical stimulation causes long-term changes in H-reflexes and spinal motoneuron GABA receptors.},
	journal = {Journal of neurophysiology},
	volume = {108},
	year = {2012},
	month = {11/2012},
	pages = {2668{\textendash}2678},
	abstract = {The cortex gradually modifies the spinal cord during development, throughout later life, and in response to trauma or disease. The mechanisms of this essential function are not well understood. In this study, weak electrical stimulation of rat sensorimotor cortex increased the soleus H-reflex, increased the numbers and sizes of GABAergic spinal interneurons and GABAergic terminals on soleus motoneurons, and decreased GABA(A) and GABA(B) receptor labeling in these motoneurons. Several months after the stimulation ended the interneuron and terminal increases had disappeared, but the H-reflex increase and the receptor decreases remained. The changes in GABAergic terminals and GABA(B) receptors accurately predicted the changes in H-reflex size. The results reveal a new long-term dimension to cortical-spinal interactions and raise new therapeutic possibilities.},
	keywords = {Spinal Cord},
	issn = {1522-1598},
	doi = {10.1152/jn.00516.2012},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/22933718},
	author = {Wang, Yu and Yi Chen and Lu Chen and Jonathan Wolpaw and Xiang Yang Chen}
}
@article {3090,
	title = {Operant conditioning of rat soleus H-reflex oppositely affects another H-reflex and changes locomotor kinematics.},
	journal = {The Journal of neuroscience : the official journal of the Society for Neuroscience},
	volume = {31},
	year = {2011},
	month = {08/2011},
	pages = {11370{\textendash}11375},
	abstract = {H-reflex conditioning is a model for studying the plasticity associated with a new motor skill. We are exploring its effects on other reflexes and on locomotion. Rats were implanted with EMG electrodes in both solei (SOL(R) and SOL(L)) and right quadriceps (QD(R)), and stimulating cuffs on both posterior tibial (PT) nerves and right posterior femoral nerve. When SOL(R) EMG remained in a defined range, PT(R) stimulation just above M-response threshold elicited the SOL(R) H-reflex. Analogous procedures elicited the QD(R) and SOL(L) H-reflexes. After a control period, each rat was exposed for 50 d to a protocol that rewarded SOL(R) H-reflexes that were above (HRup rats) or below (HRdown rats) a criterion. HRup conditioning increased the SOL(R) H-reflex to 214 {\textpm} 37\% (mean {\textpm} SEM) of control (p = 0.02) and decreased the QD(R) H-reflex to 71 {\textpm} 26\% (p = 0.06). HRdown conditioning decreased the SOL(R) H-reflex to 69 {\textpm} 2\% (p < 0.001) and increased the QD(R) H-reflex to 121 {\textpm} 7\% (p = 0.02). These changes remained during locomotion. The SOL(L) H-reflex did not change. During the stance phase of locomotion, ankle plantarflexion increased in HRup rats and decreased in HRdown rats, hip extension did the opposite, and hip height did not change. The plasticity that changes the QD(R) H-reflex and locomotor kinematics may be inevitable (i.e., reactive) due to the ubiquity of activity-dependent CNS plasticity, and/or necessary (i.e., compensatory) to preserve other behaviors (e.g., locomotion) that would otherwise be disturbed by the change in the SOL(R) H-reflex pathway. The changes in joint angles, coupled with the preservation of hip height, suggest that compensatory plasticity did occur.},
	keywords = {Rats, Sprague-Dawley},
	issn = {1529-2401},
	doi = {10.1523/JNEUROSCI.1526-11.2011},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/21813696},
	author = {Yi Chen and Lu Chen and Wang, Yu and Jonathan Wolpaw and Xiang Yang Chen}
}
@article {3095,
	title = {H-reflex up-conditioning encourages recovery of EMG activity and H-reflexes after sciatic nerve transection and repair in rats.},
	journal = {The Journal of neuroscience : the official journal of the Society for Neuroscience},
	volume = {30},
	year = {2010},
	month = {12/2010},
	pages = {16128{\textendash}16136},
	abstract = {Operant conditioning of the spinal stretch reflex or its electrical analog, the H-reflex, produces spinal cord plasticity and can thereby affect motoneuron responses to primary afferent input. To explore whether this conditioning can affect the functional outcome after peripheral nerve injury, we assessed the effect of up-conditioning soleus (SOL) H-reflex on SOL and tibialis anterior (TA) function after sciatic nerve transection and repair. Sprague Dawley rats were implanted with EMG electrodes in SOL and TA and stimulating cuffs on the posterior tibial nerve. After control data collection, the sciatic nerve was transected and repaired and the rat was exposed for 120 d to continued control data collection (TC rats) or SOL H-reflex up-conditioning (TU rats). At the end of data collection, motoneurons that had reinnervated SOL and TA were labeled retrogradely. Putative primary afferent terminals [i.e., terminals containing vesicular glutamate transporter-1 (VGLUT1)] on SOL motoneurons were studied immunohistochemically. SOL (and probably TA) background EMG activity recovered faster in TU rats than in TC rats, and the final recovered SOL H-reflex was significantly larger in TU than in TC rats. TU and TC rats had significantly fewer labeled motoneurons and higher proportions of double-labeled motoneurons than untransected rats. VGLUT1 terminals were significantly more numerous on SOL motoneurons of TU than TC rats. Combined with the larger H-reflexes in TU rats, this anatomical finding supports the hypothesis that SOL H-reflex up-conditioning strengthened primary afferent reinnervation of SOL motoneurons. These results suggest that H-reflex up-conditioning may improve functional recovery after nerve injury and repair.},
	keywords = {conditioning, peripheral nerve, plasticity, Reflex, regeneration, Spinal Cord},
	issn = {1529-2401},
	doi = {10.1523/JNEUROSCI.4578-10.2010},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/21123559},
	author = {Yi Chen and Wang, Yu and Lu Chen and Sun, Chenyou and English, Arthur W. and Jonathan Wolpaw and Xiang Yang Chen}
}
@article {3100,
	title = {Reflex conditioning: a new strategy for improving motor function after spinal cord injury.},
	journal = {Annals of the New York Academy of Sciences},
	volume = {1198 Suppl 1},
	year = {2010},
	month = {06/2010},
	pages = {E12{\textendash}E21},
	abstract = {Spinal reflex conditioning changes reflex size, induces spinal cord plasticity, and modifies locomotion. Appropriate reflex conditioning can improve walking in rats after spinal cord injury (SCI). Reflex conditioning offers a new therapeutic strategy for restoring function in people with SCI. This approach can address the specific deficits of individuals with SCI by targeting specific reflex pathways for increased or decreased responsiveness. In addition, once clinically significant regeneration can be achieved, reflex conditioning could provide a means of reeducating the newly (and probably imperfectly) reconnected spinal cord.},
	keywords = {H-Reflex, learning and memory, Locomotion, plasticity, reflex conditioning, Rehabilitation, spinal cord injury},
	issn = {1749-6632},
	doi = {10.1111/j.1749-6632.2010.05565.x},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/20590534},
	author = {Xiang Yang Chen and Yi Chen and Wang, Yu and Thompson, Aiko and Jonathan S. Carp and Segal, Richard L. and Jonathan Wolpaw}
}
@article {3151,
	title = {Recovery of electromyographic activity after transection and surgical repair of the rat sciatic nerve.},
	journal = {Journal of neurophysiology},
	volume = {97},
	year = {2007},
	month = {02/2007},
	pages = {1127{\textendash}1134},
	abstract = {The recovery of soleus (SOL), gastrocnemius (GAS), and tibialis anterior (TA) electromyographic activity (EMG) after transection and surgical repair of the sciatic nerve was studied in Sprague-Dawley rats using chronically implanted stimulation and recording electrodes. Spontaneous EMG activity in SOL and GAS and direct muscle (M) responses to posterior tibial nerve stimulation persisted for < or =2 days after sciatic nerve transection, but SOL and GAS H-reflexes disappeared immediately. Spontaneous EMG activity began to return 2-3 wk after transection, rose nearly to pretransection levels by 60 days, and persisted for the duration of the study period (120 days). Recovery of stimulus-evoked EMG responses began about 30 days after sciatic nerve transection as multiple small responses with a wide range of latencies. Over time, the latencies of these fractionated responses shortened, their amplitudes increased, and they merged into a distinct short-latency component (the putative M response) and a distinct long-latency component (the putative H-reflex). The extent of recovery of stimulation-evoked EMG was modest: even 100 days after sciatic nerve transection, the responses were still much smaller than those before transection. Similar gradual development of responses to posterior tibial nerve stimulation was also seen in TA, suggesting that some regenerating fibers sent branches into both tibial and common peroneal nerves.},
	keywords = {Tibial Nerve},
	issn = {0022-3077},
	doi = {10.1152/jn.01035.2006},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/17122310},
	author = {English, Arthur W. and Yi Chen and Jonathan S. Carp and Jonathan Wolpaw and Xiang Yang Chen}
}
@article {3150,
	title = {Spinal and supraspinal effects of long-term stimulation of sensorimotor cortex in rats.},
	journal = {Journal of neurophysiology},
	volume = {98},
	year = {2007},
	month = {08/2007},
	pages = {878{\textendash}887},
	abstract = {Sensorimotor cortex (SMC) modifies spinal cord reflex function throughout life and is essential for operant conditioning of the H-reflex. To further explore this long-term SMC influence over spinal cord function and its possible clinical uses, we assessed the effect of long-term SMC stimulation on the soleus H-reflex. In freely moving rats, the soleus H-reflex was measured 24 h/day for 12 wk. The soleus background EMG and M response associated with H-reflex elicitation were kept stable throughout. SMC stimulation was delivered in a 20-day-on/20-day-off/20-day-on protocol in which a train of biphasic 1-ms pulses at 25 Hz for 1 s was delivered every 10 s for the on-days. The SMC stimulus was automatically adjusted to maintain a constant descending volley. H-reflex size gradually increased during the 20 on-days, stayed high during the 20 off-days, and rose further during the next 20 on-days. In addition, the SMC stimulus needed to maintain a stable descending volley rose steadily over days. It fell during the 20 off-days and rose again when stimulation resumed. These results suggest that SMC stimulation, like H-reflex operant conditioning, induces activity-dependent plasticity in both the brain and the spinal cord and that the plasticity responsible for the H-reflex increase persists longer after the end of SMC stimulation than that underlying the change in the SMC response to stimulation.},
	keywords = {Time Factors},
	issn = {0022-3077},
	doi = {10.1152/jn.00283.2007},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/17522179},
	author = {Xiang Yang Chen and Pillai, Shreejith and Yi Chen and Wang, Yu and Lu Chen and Jonathan S. Carp and Jonathan Wolpaw}
}
@article {3190,
	title = {Corticospinal tract transection permanently abolishes H-reflex down-conditioning in rats.},
	journal = {Journal of neurotrauma},
	volume = {23},
	year = {2006},
	month = {11/2006},
	pages = {1705{\textendash}1712},
	abstract = {Previous studies have shown that corticospinal tract (CST) transection, but not transection of other major spinal cord tracts, prevents down-conditioning of the H-reflex, the electrical analog of the spinal stretch reflex. This study set out to determine whether the loss of the capacity for H-reflex down-conditioning caused by CST transection is permanent. Female Sprague-Dawley rats received CST, lateral column (LC), or dorsal column ascending tract (DA) transection at T8-9; 9-10 months later, they were exposed to the H-reflex down-conditioning protocol for 50 days. In the LC and DA rats, H-reflex size fell to 60 (+/- 9 SEM)\% and 60 (+/- 19)\%, respectively, of its initial size. This down-conditioning was comparable to that of normal rats. In contrast, H-reflex size in the CST rats rose to 170 (+/- 42)\% of its initial size. A similar rise does not occur in rats exposed to down-conditioning shortly after CST transection. These results indicate that CST transection permanently eliminates the capacity for H-reflex down-conditioning and has gradual long-term effects on sensorimotor cortex function. They imply that H-reflex down-conditioning can be a reliable measure of CST function for long-term studies of the effects of spinal cord injury and/or for evaluations of the efficacy of experimental therapeutic procedures, such as those intended to promote CST regeneration. The results also suggest that the role of sensorimotor cortex in down-conditioning extends beyond generation of the essential CST activity.},
	keywords = {corticospinal tract, H-reflex conditioning, plasticity, rat, spinal cord injury},
	issn = {0897-7151},
	doi = {10.1089/neu.2006.23.1705},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/17115915},
	author = {Xiang Yang Chen and Yi Chen and Lu Chen and Tennissen, Ann M. and Jonathan Wolpaw}
}
@article {3066,
	title = {Operant conditioning of H-reflex can correct a locomotor abnormality after spinal cord injury in rats.},
	journal = {The Journal of neuroscience : the official journal of the Society for Neuroscience},
	volume = {26},
	year = {2006},
	month = {11/2006},
	pages = {12537{\textendash}12543},
	abstract = {<p>This study asked whether operant conditioning of the H-reflex can modify locomotion in spinal cord-injured rats. Midthoracic transection of the right lateral column of the spinal cord produced a persistent asymmetry in the muscle activity underlying treadmill locomotion. The rats were then either exposed or not exposed to an H-reflex up-conditioning protocol that greatly increased right soleus motoneuron response to primary afferent input, and locomotion was reevaluated. H-reflex up-conditioning increased the right soleus burst and corrected the locomotor asymmetry. In contrast, the locomotor asymmetry persisted in the control rats. These results suggest that appropriately selected reflex conditioning protocols might improve function in people with partial spinal cord injuries. Such protocols might be especially useful when significant regeneration becomes possible and precise methods for reeducating the regenerated spinal cord neurons and synapses are needed for restoring effective function.</p>},
	keywords = {H-reflex conditioning, Learning, Locomotion, Memory, Motor control, Rehabilitation, spinal cord injury, spinal cord plasticity},
	issn = {1529-2401},
	doi = {10.1523/JNEUROSCI.2198-06.2006},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/17135415},
	author = {Yi Chen and Xiang Yang Chen and Jakeman, Lyn B. and Lu Chen and Stokes, Bradford T. and Jonathan Wolpaw}
}
@article {3191,
	title = {Operant conditioning of reciprocal inhibition in rat soleus muscle.},
	journal = {Journal of neurophysiology},
	volume = {96},
	year = {2006},
	month = {10/2006},
	pages = {2144{\textendash}2150},
	abstract = {Operant conditioning of the H-reflex, the electrical analog of the spinal stretch reflex (SSR), induces activity-dependent plasticity in the spinal cord and might be used to improve locomotion after spinal cord injury. To further assess the potential clinical significance of spinal reflex conditioning, this study asks whether another well-defined spinal reflex pathway, the disynaptic pathway underlying reciprocal inhibition (RI), can also be operantly conditioned. Sprague-Dawley rats were implanted with electromyographic (EMG) electrodes in right soleus (SOL) and tibialis anterior (TA) muscles and a stimulating cuff on the common peroneal (CP) nerve. When background EMG in both muscles remained in defined ranges, CP stimulation elicited the TA H-reflex and SOL RI. After collection of control data for 20 days, each rat was exposed for 50 days to up-conditioning (RIup mode) or down-conditioning (RIdown mode) in which food reward occurred if SOL RI evoked by CP stimulation was more (RIup mode) or less (RIdown mode) than a criterion. TA and SOL background EMG and TA M response remained stable. In every rat, RI conditioning was successful (i.e., change > or =20\% in the correct direction). In the RIup rats, final SOL RI averaged 171+/- 28\% (mean +/- SE) of control, and final TA H-reflex averaged 114 +/- 14\%. In the RIdown rats, final SOL RI averaged 37 +/- 13\% of control, and final TA H-reflex averaged 60 +/- 18\%. Final SOL RI and TA H-reflex sizes were significantly correlated. Thus like the SSR and the H-reflex, RI can be operantly conditioned; and conditioning one reflex can affect another reflex as well.},
	keywords = {Reflex, Stretch},
	issn = {0022-3077},
	doi = {10.1152/jn.00253.2006},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/16807351},
	author = {Xiang Yang Chen and Lu Chen and Yi Chen and Jonathan Wolpaw}
}
@article {3194,
	title = {The interaction of a new motor skill and an old one: H-reflex conditioning and locomotion in rats.},
	journal = {The Journal of neuroscience : the official journal of the Society for Neuroscience},
	volume = {25},
	year = {2005},
	month = {07/2005},
	pages = {6898{\textendash}6906},
	abstract = {New and old motor skills can interfere with each other or interact in other ways. Because each skill entails a distributed pattern of activity-dependent plasticity, investigation of their interactions is facilitated by simple models. In a well characterized model of simple learning, rats and monkeys gradually change the size of the H-reflex, the electrical analog of the spinal stretch reflex. This study evaluates in normal rats the interactions of this new skill of H-reflex conditioning with the old well established skill of overground locomotion. In rats in which the soleus H-reflex elicited in the conditioning protocol (i.e., the conditioning H-reflex) had been decreased by down-conditioning, the H-reflexes elicited during the stance and swing phases of locomotion (i.e., the locomotor H-reflexes) were also smaller. Similarly, in rats in which the conditioning H-reflex had been increased by up-conditioning, the locomotor H-reflexes were also larger. Soleus H-reflex conditioning did not affect the duration, length, or right/left symmetry of the step cycle. However, the conditioned change in the stance H-reflex was positively correlated with change in the amplitude of the soleus locomotor burst, and the correlation was consistent with current estimates of the contribution of primary afferent input to the burst. Although H-reflex conditioning and locomotion did not interfere with each other, H-reflex conditioning did affect how locomotion was produced: it changed soleus burst amplitude and may have induced compensatory changes in the activity of other muscles. These results illustrate and clarify the subtlety and complexity of skill interactions. They also suggest that H-reflex conditioning might be used to improve the abnormal locomotion produced by spinal cord injury or other disorders of supraspinal control.},
	keywords = {H-reflex conditioning, Learning, Locomotion, memory consolidation, Motor control, Rehabilitation, spinal cord plasticity},
	issn = {1529-2401},
	doi = {10.1523/JNEUROSCI.1684-05.2005},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/16033899},
	author = {Yi Chen and Xiang Yang Chen and Jakeman, Lyn B. and Gerwin Schalk and Stokes, Bradford T. and Jonathan Wolpaw}
}
